Do you have already more experience with more then 4-5 Sensors.

@cabat : Thanks for sharing. When do you plan to connect more nodes? How long will be the cables?

General Question: I saw as well the ESPhome.io which looks very nice for me. Is this something which can be combined with the mySensors protocol? I want to use NodeRed in the OrangePi Gateway to gather all the sensor values.

Thanks for the proposal.
I have still one concern to use RS485:
My topology would be star topology, but RS485 is not designed for that.
Do someone have already experience with that?
Will it work with a lower baudrathe around 19,2k?
How big delay can I expect by using a motion detection sensor to switch on the lights?

Thanks for the reply.
A rs485 sounds pretty good.
Do we have already a cheap board to put temp humidity motion sensor together on a mySensor board?
I was thinking already about the si7021 Sensor and an cheap rf sensor with an digital output.
As an gateway I have a orangePi Zero with nodeRed in mind.

Hello together,
I see that here are the experts of sensors for smart buildings.

I build some years ago my smart home with the general idea to keep as much as possible everything wired.
I prepared to each heating distributor a LAN cable and from the heating distributor a 4x0,8qmm cable do the sensor pleace for each room.
Now I would like to put a gateway in each heating distributor which collect all the data from the sensors in the room.
Nice to have would be to have in each room a temp, humidity, light & move(rf) sensor.
My issue is now that I have only 4 signal(wire) to the gateway, so that I need sensor which have the same fieldbus or I2C or something else.
The latest would be to have a microcontroller on the sensor side which collect the sensor data and send it to the gateway.

Would be great if you can advise if there is some suitable solution for my requirements.
I would like to use only wired connection no rf.
Best regards